Almost 2 years ago I replaced a Ford F150 with the 4.6L V-8 and automatic transmission with a 2008 Nissan Frontier with a 6 speed manual transmission.
I find the Nissan to be superior to the Ford for towing both my 19' 3,530 Dry -4,500 lb Max and my 21' 3,900 Dry - 5,500 lb Max, particularly in the mountains. Both trucks have about the same HP, but the Nissan has a better range of gear ratios for towing. I'm not sure how the automatic transmission would compare.
4 wheel drive is particularly useful with the low range to position the trailer in rough terrain if you are into boondocking.
p.s. The Nissan Frontier is rated to tow 6,500 lb